The present invention relates to telecommunications systems and, in particular, to the telephone local loop plant.
The access network interconnecting telephone central offices and terminal equipment at customer premise locations is conventionally referred to as the "local loop plant." This network is comprised, for each so-called "line," or "local loop," of a series of local loop segments extending from within a central office, through various cross-connection elements, to endpoints connected to the customer premises locations. In strictly-wire-pair-based arrangements, these cross-connection elements typically include the main distributing frame within the central office building; one or more feeder/distribution interfaces (FDIs) and/or cross-connects, typically housed in grade-level or aerial pedestal cabinets, or huts, or in subterranean vaults; and a serving terminal typically housed in an enclosure mounted on a utility pole or in a pedestal or on, or within, a building. The segment of the local loop extending between the central office and the FDI is called a feeder pair and may comprise a physical pair of wires or may comprise a "virtual" feeder pair in the form of a digital loop carrier (DLC) timeslot. The local loop segments extending beyond the FDI are called distribution pairs. And the segment extending from the serving terminal to the subscriber premises is called the drop pair, or drop.
The process of provisioning new wire-pair-based local loops and performing maintenance on the existing local loops is an expensive one. One principal source of expense is the labor cost associated with the need to dispatch craftpersons into the field to manually make cross-connections in the FDIs and serving terminals. In turn, a major part of this labor cost arises out of the fact that the typical new line or maintenance change in the local loop plant requires a number of rearrangements and that for a significant proportion of those rearrangements, an error is made--either in the rearrangement itself or in one or more administrative database entries that need to be made in consequence of the changes--engendering yet additional expense in order to correct the errors.
Another source of expense is the phenomenon called "churn" in which it becomes necessary to tear apart and reconfigure perfectly good individual loops and/or whole sections of the narrowband plant-borrowing from Peter to pay Paul--in order to accommodate an unexpected, and therefore unplanned-for, level of demand for new narrowband service in an area; or in order to provide wire-pair-based broadband, e.g., T1 or ISDN service; or in order to deal with maintenance problems that have arisen.
Yet another significant source of expense arises from the fact that the provisioning and maintenance of the existing local loop plant infrastructure involves the accessing and updating of records in as many as six or more administrative database systems. These administrative database systems contain, for example, detailed data for each local loop, specifying, among much other information, all of the local loop's feeder, distribution and drop pairs so that telephone craftpersons can, for example, a) identify which wire pairs between any two cross-connection elements are available to form newly provisioned loops, and b) troubleshoot reported local loop problems. This information is used in the course of managing and/or implementing such functions as order entry, service order processing, facilities assignment, installation, memory administration, trouble receipt, testing, trouble analysis and craftperson dispatch. Those skilled in art are quite familiar with such systems as COSMOS, LFACS and PREMIS used extensively throughout the so-called regional Bell operating companies (RBOCS). Given that these systems were developed in the 1970's and 80's at a time prior to the break-up of the Bell System in 1984, they represent a kind of legacy from the Bell System of the past, and indeed have come to be known in the art as the "legacy systems."
More specifically on the expense issue, the mere fact that the numerous functions just mentioned are divided up among many systems translates into high labor costs for database entry clerks, trainers to train those clerks and personnel to maintain the hardware and software of the various systems. In addition, the legacy systems were developed largely independently of one another over a period of time and, indeed, are fairly self-contained and operate pretty much independently of one another. As a result, they contain a great deal of redundant information. Thus each change in a subscriber's service necessitates making separate, often redundant entries in at least a number of these systems. Not only is this redundancy a cost factor in and of itself, but it also gives rise to additional costs associated with correcting the inevitable inconsistencies that, as the result of human error, occur among the databases maintained by the various systems. Moreover, the legacy systems are based on old technology, including mainframe computers that are dinosaurs by today's standards. Those computers require a great deal more maintenance and servicing than present-day computer systems, which adds further to their operational costs. Moreover, the legacy systems have cumbersome user interface characteristics which make them difficult, and thus expensive, to learn and to operate.
These problems will ultimately be obviated once the next generation of local access distribution systems has been put in place. In particular, each of the RBOCS is currently preparing, or has already begun, to transition its current local loop plant from the current narrowband wire pairs and DLCs to a broadband plant capable of supporting the many broadband services that are promised for the future, including, for example, video telephony, movies-on-demand, multimedia information access, high-speed data network access, and network-based games. Among the broadband local loop technologies currently being deployed or planned for deployment are so-called fiber-to-the-home, switched digital video and hybrid fiber coax.
Significantly, these broadband facilities are, or will be, administered by their own, state-of-the-art administrative database systems which do not suffer from the various limitations of the legacy systems as outlined above. For example, all of the administrative functionalities associated with AT&T's hybrid fiber coax technology-provisioning, testing and maintenance--are to be carried out by a single, integrated administrative database system, known as ASOS. Since all of the administrative functions will be carried out by a single system, the problems associated with having a multiplicity of systems are obviated. Moreover, ASOS will need to have far less functionality than the legacy systems because, for example, many provisioning and administrative tasks are carried out in the hybrid fiber coax facilities automatically and/or dynamically. This greatly cuts down on the amount of database clerk activity that is needed, and also greatly reduces the amount of data that needs to be stored about any particular local loop. Moreover, the hybrid fiber coax loops are all of one kind-dynamically assigned optical transmission system timeslots from the central office to a remote terminal, and coaxial cable channels from there to a so-called "tap" (which takes the place of the above-mentioned serving terminal used in wire-pair-based systems) and from the tap into the customer premises. This is in contrast to the existing narrowband plant, which includes a large number of different kinds of feeder and distribution pairs-loaded and unloaded, heavy gauge and thin gauge, etc.--which are allowed to be configured with one another in a myriad of different ways, requiring, in turn, administrative database systems which are sufficiently complex to account for all of that flexibility.
Unfortunately, it will be well into the next century before the country's local loop plant has been substantially converted from narrowband to broadband and, in the meantime, the existing narrowband loop plant must continue to be administered. However, the costs of continuing to use the legacy systems in their current form are so great that executives in the local operating companies are actively-indeed desperately-searching for something to do other than simply continue to suffer with what they have.
One apparent solution would be to commission the development of a completely new administrative system for the narrowband plant that would replicate the functionality of the legacy systems in a single system based on state-of-the-art hardware, software, database and user interface technology. It is well understood, however, that the legacy systems are, for many reasons, so complex, that the cost of designing and developing a system that would replicate their functionalities would be prohibitive--perhaps as much as $1 billion. This would be a hefty price to pay for a system whose only function would be to administer a local loop plant whose days are clearly numbered.
Another, possibly less expensive, alternative would be to somehow fix or upgrade the legacy systems without completely replacing them. However, there seems to be no clear idea of how to go about doing that.
At the moment, then, it would appear to the local operating companies that they have little alternative but to sit back and await the day, as much as 10-20 years hence, when the last of the narrowband facilities, and their ever-so-expensive and burdensome legacy administrative systems, have finally been retired from service.